This invention relates to the field of twisting technology for electric and optical cables in general and more particularly to an arrangement for increasing the operating speed of apparatus for the ceander shaped application of metal wires or optical elements on a core.
In the manufacture of electric cables with a shield or concentric conductor built up from individual wires, i.e., a ceander shaped conductor, it has been customary for a long time to apply, for production and/or installation reasons, the metal wires to the cable core consisting of a conductor or a twisting group with a direction of lay which changes at short intervals (DE-OS 15 40 432). For manufacturing such a ceander conductor (See Siemens-Elecktrodienst, No. 2, 1966, pages 10 and 11), an apparatus is used which includes a perforated disc which revolves with a sinusoidal oscillation, guides the metal wires and together with a preceding guide tube for guiding the cable core and for temporarily receiving the shield wires as well as with a stationary perforated disc arranged at the start of this guide tube. This forms what is known as a tube accumulator SZ twisting machine (DE-GM 66 08 174).
The operation of such a machine causes difficulties inasmuch as the metal wires are subjected, in the region between the two perforated discs, to periodic length variations which bring about variations of the tension all the way into the twisting closer which immediately follows the oscillating perforated disc. It has been attempted to counteract the resulting limited operating speed of the machine by controlling the tension of the metal wires. For this purpose, in part rather expensive control measures have been provided at the supply reels of the wires or on the way from the supply reels to the stationary perforated disc (DE-OS 20 36 532, DE-OS 16 40 309).
Another way of eliminating tension variations is by arranging a further perforated disc which oscillates with shifted phase relative to the main oscillating perforated disc between the stationary and the oscillating perforated disc. The spacing of the perforated discs from each other may be variable here. By arranging a fourth perforated disc it is supposed to be possible to compensate for uneven motion of the wires. The hole circle diameters of the perforated discs are kept as small as possible (DE-GM 66 08 280).
Starting out from a tube accumulator SZ twisting machine for applying ceander shaped metal wires on a core formed by a conductor on twisting group of an electric cable which includes a stationary cylindrical tube, through which the core is conducted, perforated discs at the beginning and end of the tube through which the metal wires pass, the disc having a pitch diameter greater than that of the tube, the perforated disc at the beginning of the tube fixed and that at the end of the tube adapted to be oscillated with an angle of rotation about the axis of the tube of at most .+-.360.degree.; and a twisting closer immediately following the oscillating disc, and in which the wires are stranded on the core by the oscillating disc, it is an object of the present invention to develop this apparatus further in such a manner that the metal wires or optical elements may be applied to a cable core free of troublesome tension variations, without using control or regulating devices.